U.S. to Produce Data on Iran’s Nuclear Program

The Bush administration has agreed to turn over to international inspectors intelligence data it has collected that it says proves Iran worked on developing a nuclear weapon until a little more than four years ago, according to American and foreign diplomats.

The decision reverses the United States’ longstanding refusal to share the data, citing the need to protect intelligence sources.

The administration acted as the International Atomic Energy Agency is scheduled to issue a report as early as next week on Iran’s past nuclear activities. Administration officials hope that the nuclear inspectors can now confront Iran with what the Americans believe is the strongest evidence that the Iranians had a nuclear program.

The Bush administration’s refusal to turn over the data has been a source of friction with Mohammed ElBaradei, the director general of the agency, who has argued that Iran must be given a fair chance to examine some of the case that Washington has developed.

But it remains unclear how much of the data Dr. ElBaradei will be allowed to disclose to the Iranians. In particular, it is not clear if the information includes diagrams and designs that were secretly taken out of Iran on a laptop computer in 2004 and turned over to the Central Intelligence Agency.

Under the terms of a “work plan” concluded last summer, Iran was to have met a series of deadlines set by the agency to resolve any unanswered questions about its nuclear activities.

Dr. ElBaradei is eager to resolve all of the outstanding questions before he issues his next report to the agency’s 35-member board, which could be as early as the end of next week.

The Bush administration’s decision came two months after the publication of a National Intelligence Estimate that concluded, with what it terms “high confidence,” that Iran was designing a weapon through 2003. But the assessment indicated that Iranian officials ordered the work halted later that year, perhaps because they feared it would ultimately be discovered.

The publication of the new estimate in early December undercut efforts to toughen sanctions that were initially imposed because Iran refused to follow a United Nations Security Council demand that it stop enriching uranium.

On Sunday, in an interview with Fox News, Mr. Bush made it clear that he disagreed with the idea that the intelligence estimate lowered the threat from Iran. “Iran is a threat, and that’s what the N.I.E. said, if you read it carefully,” he said. “It showed they had a weapons — secret military weapons program, but that doesn’t mean they can’t have another secret weapons military program.”

According to American and foreign officials interviewed about the contents of the laptop, the information found there included descriptions of the so-called Green Salt Project. That project, which involved uranium processing, high explosives and a missile warhead design, demonstrated what the agency suspected were links between Iran’s military and its ostensibly peaceful nuclear program. If that evidence were substantiated, it would undercut Iran’s claims that its program is aimed solely at producing electrical power.

The documents on the laptop described two programs, termed L-101 and L-102 by the Iranians, describing designs and computer simulations that appeared to be related to weapons work.

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Iran, while dismissing as baseless the assertions that such a program existed, agreed to examine documents that the United States said pertained to Green Salt. But Iran has said it wants to take possession of the documents, something the United States has refused to allow.

Iran could cry foul unless the Americans turn over the documents, which Dr. ElBaradei said it has a right to have.

“We have to give them access to the documents — I think it’s fair,” he said in an interview last August. “I’m a lawyer, and due process will tell me that I cannot accuse a person without providing him or her with the evidence.” He added, “I can’t accuse a country saying, ‘You will get your charges but I am not going to tell you what the charges are.’ ”

Officials cautioned that they did not know whether the information to be shared with Iran would be enough to persuade the country to be more forthcoming about certain aspects of its past nuclear activities.

The most likely outcome, officials said, is that Iranian officials will be allowed to view a sanitized presentation, similar to the one that American intelligence officials showed in 2005 to countries it was trying to persuade to vote for sanctions against Iran.

The presentation included selections from more than a thousand pages of Iranian computer simulations and accounts of experiments that, according to the American officials, showed a longstanding effort to design what appeared to be a nuclear warhead or similar “re-entry vehicle.”

In recent months, France, Britain and Germany have been strongly urging the United States to turn over to Iran any relevant intelligence information, including documents found on the laptop, that could shed light on Iran’s nuclear history, European officials said. The Europeans did not want Iran to avoid cooperating fully in revealing its past by trying to blame the United States.

While Dr. ElBaradei is trying to bring the outstanding past issues to closure before he issues his report on the status of the Iranian program, the officials said that they were doubtful that Iran could clear up the remaining questions in such a short time.

On Thursday, Dr. ElBaradei met in Paris with President Nicolas Sarkozy and other senior French officials, who urged him to be firm with Iran, stressing that the credibility of his agency was at stake.

France has taken a hard line against Iran, joining the United States and Britain in pressing for new, tougher international sanctions against the country for flouting Security Council resolutions demanding that it stop making nuclear fuel.

In a speech on Wednesday night to France’s Jewish community, Mr. Sarkozy called on Iran to “renounce military nuclear power” and “live up to its word.” He added that Iran’s uranium enrichment program “has no civilian purpose.”

David E. Sanger reported from Washington, and Elaine Sciolino from Paris. William J. Broad contributed reporting from New York.

A version of this article appears in print on , on Page A9 of the New York edition with the headline: In a Reversal, U.S. Agrees to Produce Data Pointing to Iran’s Nuclear Ambitions. Order Reprints|Today's Paper|Subscribe